Asthma is a progressive inflammatory disease of the lungs that leads to structural airway changes and debilitating symptoms in many affected children and adults. It is the most common chronic childhood disease, and asthma attacks are the most common reason children miss school. More than 5 million children have asthma and the prevalence of asthma in some inner cities in the United States is greater than 20%. While environmental triggers are recognized as key parameters in managing pediatric asthma, it has been challenging to concurrently measure health metrics in children at the same time as quantifying the triggers to which they are being exposed. A technology gap has existed for portable monitoring systems that can perform these functions simultaneously while continuously logging data. This project will develop a safe and effective wearable diagnostic health monitoring sensor for children with asthma to improve their daily quality of life. It will combine four major functions in a single packaged system worn by the user: (1) routine portable spirometry and pulmonary lung function measurements can be taken and logged by the user on-demand; (2) exhaled breath oxylipin biomarkers can be measured and logged in near-real-time by the user on-demand; (3) environmental chemical monitoring will be continuously logged to understand background triggers of asthma; (4) patient symptoms and drug use will be manually logged by the user enabled by an intuitive graphical user interface. In a prior pediatric asthma clinical trial using breath monitoring, we found that eicosanoids were measureable in exhaled breath and were consistent with the levels needed for detection using the novel and portable instruments we have developed. For this period, we aim: 1) To establish a wearable sensor system architecture integrating our modular components into a total breath monitoring system capable of: spirometry, real-time eicosanoid measurements, and continuous environmental chemical monitoring, and 2) To enroll 10 adolescent asthmatic subjects to use the new wearable sensor in a longitudinal pilot clinical trial over 8 months to test the hypothesis that increased breath eicosanoid levels correlate with increased asthma symptoms and worse lung function. At the end of this study, we anticipate our prototype system will have been benchmarked for use specifically in pediatric asthma metabolite monitoring. Our goal is to improve asthma monitoring for all children.